> 
> > are you sure? when/how often does "last midas program finishes" happen? it does not happen on a system crash, not on power loss, not on "shutdown -r now" 
> > (I am pretty sure). In the experiments you run, how often do you shut down all programs (and check that you did not forget one somehow)?
> 
> Indeed this is almost never the case, maybe once per months. On the other hand, we have a complete crash of the os maybe once a year. Most of the time the programs 
> run continuously (we do not need odbedit), so our timestamp is typically one or two days old, so not good either.
> 
> > my vote is to undo this change, it is dangerous because it causes odb to be saved to ODB.SHM never.
> 
> My vote is to flush the odb either periodically or after each run.
> 

So we are in agreement.

RFE filed:
https://bitbucket.org/tmidas/midas/issues/367/odb-should-be-saved-to-disk-periodically

Dangerous change reverted:
60e4c44ad66346b89ba057391acf7a02890049be

K.O.

bash-3.2$ git diff
diff --git a/src/odb.cxx b/src/odb.cxx
index 0d3b88c2..d104ff28 100644
--- a/src/odb.cxx
+++ b/src/odb.cxx
@@ -2199,7 +2199,14 @@ INT db_close_database(HNDLE hDB)
       destroy_flag = (pheader->num_clients == 0);
 
       /* flush shared memory to disk */
-      if (destroy_flag)
+
+      /* if we save ODB to disk only after last client finishes, we will never save ODB to disk
+         in most experiments - none of them ever completely stop MIDAS in normal operation.
+         as result, all changes to ODB contents will be lost on system crash, power loss
+         or normal reboot. see https://daq00.triumf.ca/elog-midas/Midas/2539
+         K.O. June 2023. */
+
+      if (1 || destroy_flag)
          ss_shm_flush(pheader->name, pdb->shm_adr, pdb->shm_size, pdb->shm_handle);
 
       strlcpy(xname, pheader->name, sizeof(xname));

K.O.